The development of a rapid, specific and sensitive assay for Bordetella pertussis organisms from nasopharyngeal or throat swabs is necessary to screen young children with severe respiratory infections and older children and adults which have made conact with the disease. Vaccines have reduced Whooping Cough cases, but even these numbers may be underestimated. Standard detection methods are very difficult. Culturing and direct fluorescent antibody techniques are insensitive and non-specific. An enzyme immunoassay which detects infectious organisms during the early stages of the disease will allow effective initiation of antibiotic treatment. Highly specific antibodies and enzyme systems will be used to indicate the presence of B. pertussis organisms in clinical specimens. The organisms-antibody-enzyme(s) are trapped on a membrane filter and substrate/chromagen solution will be added. Color production will indicate the presence of infectious B. pertussis organisms. This method will be rapid, sensitive, specific and does not require elaborate and expensive laboratory equipment. The feasibility of this detection system is expected to be demonstrated in Phase I and an assay sensitive to very low concentrations of pathogenic organisms is expected to be developed and optimized in Phase II. During Phase II, the system will be converted to a simple, specific dip and read strip assay format.